Standard 90 gallon

[shua71]

From personal experiece, I would worry more about the tank cracking and spilling that much water on the floor. I had a 50 gallon crack and in about 3 minutes, 50 gallons of water was on the floor.

It can cause water damage and will leak to the bottom floor. But yea, it might never happen to you. Guess you have to have faith in your tank.

That would be a horrible issue to have... But what difference would keeping it on the first floor actually make? You'd still have 50 gallons on the floor to clean up and mold and everything to solve.

 

[12 Volt Man]

because water works its way down. if it happens when you are not around, by the time you get to it, the water has seeped down to the first floor so now you have damage on both floors.